[Wowfunhappy]

My Panic PlayDate, which lacks the paper-like contrast of e-ink but can refresh at 50 fps, looks fantastic in direct sunlight. I believe it’s using a Sharp Memory LCD.

So there is other tech for this.

[dleslie]

But it's just black and white, right? Still, that sounds promising.

[Wowfunhappy]

Yes, and the pixels can only be either black or white, not shades of grey. (Although dithering is surprisingly effective.)

My Pebble Time Smartwatch had a color memory LCD which was also easy to read in direct sunlight, but the PlayDate's screen looks a lot better.